1. Field of the Invention
The present invention relates to a jaw cylinder in a jaw folder for a rotary press. In particular, it relates to a jaw cylinder in a jaw folder, which is possible to adjust a gap between a stationary (non-open/close) member and a swing (open/close) member in a jaw mechanism during operation.
2. Description of the Related Art
Publicly known jaw cylinders capable of adjusting a gap between a stationary member and a swing member in a jaw mechanism during operation include those disclosed in Japanese Patent Publication No. 7-55761 and Japanese Patent Nos. 2637067, 2779140 and 2848982, for example.
JP 7-55761 describes a jaw cylinder equipped with an adjustment mechanism capable of adjusting a gap between a stationary member and a swing member in a jaw mechanism based on a result obtained from on-machine measurement of a thickness of a web to be processed. This jaw cylinder has a jaw cylinder shaft rotatably supported on two opposite frames. A first member provided with the stationary member in the jaw mechanism and a second member provided with the swing member in the jaw mechanism are attached to the jaw cylinder shaft rotatably about the rotational centerline thereof. The jaw cylinder shaft further includes a first, a second and a third adjustment shafts. The first adjustment shaft is possible to rotate in synchronization with the jaw cylinder shaft. The first adjustment shaft has the rotational centerline coincident with the rotational centerline of the jaw cylinder shaft. The second adjustment shaft is possible to rotate about the second rotational centerline that is perpendicular to the rotational centerline of the jaw cylinder shaft and extends in the radial direction of the jaw cylinder. The second adjustment shaft is linked through a bevel gear to the first adjustment shaft to receive rotations therefrom. The third adjustment shaft is possible to rotate about the third rotational centerline that is perpendicular to the rotational center line of the jaw cylinder and to the second rotational centerline. The third adjustment shaft is linked through a bevel gear to the second adjustment shaft to receive rotations therefrom. The third adjustment shaft has one end screwed into a female threaded member attached to the first member and the other end screwed into a female threaded member attached to the second member. The jaw cylinder shaft and the first and second members are configured to rotate synchronously. On the basis of the above measured result, it rotates the first adjustment shaft relative to the jaw cylinder shaft, then rotates the third adjustment shaft through the second adjustment shaft, and turns the first and second members oppositely about the rotational centerline of the jaw shaft. The gap between the stationary and swing members in the jaw mechanism can be adjusted by widening/narrowing the gap by an equivalent amount oppositely from the location of a blade for inserting a print therebetween.
JP 263067 describes a jaw cylinder equipped with an adjustment mechanism capable of adjusting a gap between a stationary member and a swing member in a jaw mechanism. This jaw cylinder has a jaw cylinder shaft rotatably supported on two opposite frames. A first member provided with the stationary member in the jaw mechanism and a second member provided with the swing member in the jaw mechanism are attached to the jaw cylinder shaft rotatably about the rotational centerline thereof. The jaw cylinder shaft also includes an adjustment shaft that is rotatable around the same rotational centerline as the jaw cylinder shaft synchronously therewith and movable along the rotational centerline of the jaw cylinder shaft. The adjustment shaft has a groove tilted to the moving direction thereof. The jaw cylinder shaft further includes an adjustment arm that has one end linked to the groove and is movable in the direction perpendicular to the rotational centerline and in the radial direction of the jaw cylinder. On the other end of the adjustment arm, two axially symmetric slopes are arranged in parallel with the rotational centerline and equally tilted to the moving direction of the arm. One of the slopes is formed in contact with the first member and the other the second member. This adjusting mechanism allows the jaw cylinder shaft and the first and second members to rotate synchronously. A male threaded member is coupled through a bearing to the adjustment shaft on the same rotational centerline and is screwed into a female screw secured on a frame. When the male threaded member is rotationally operated to move the adjustment shaft along the rotational centerline, the adjustment arm is displaced in the radial direction. The two axially symmetric slopes on the adjustment arm are employed to turn the first and second members, which contact respectively with the two slopes, oppositely about the rotational centerline of the jaw shaft. The gap between the stationary and swing members in the jaw mechanism can be adjusted by widening/narrowing the gap by an equivalent amount oppositely from the location of a blade for inserting a print therebetween.
JP 2779140 describes a jaw cylinder equipped with an adjustment mechanism capable of adjusting a gap between a stationary member and a swing member in a jaw mechanism. This jaw cylinder has a jaw cylinder shaft rotatably supported on two opposite frames. A first member provided with the stationary member in the jaw mechanism is attached to the jaw cylinder shaft rotatably about the rotational centerline thereof. A second member provided with the swing member in the jaw mechanism is attached to an eccentric location on the first member. A gear mechanism is provided to transmit rotations from the jaw cylinder shaft to the first member so as to rotate the first member in synchronization with the jaw cylinder shaft. The torsion of a helical gear in the gear mechanism is employed to turn the first member relative to the jaw cylinder shaft about the rotational centerline of the jaw cylinder shaft. The angular displacement of the first member is transmitted to the second member through another gear or link mechanism. The second member is turned relative to the first member in the direction opposite to the direction of the angular displacement of the first member to move the swing member close to and apart from the stationary member. This arrangement is operative to turn the first member relative to the jaw cylinder shaft and turn the second member relative to the first member. The gap between the stationary and swing members in the jaw mechanism can be adjusted by widening/narrowing the gap by an equivalent amount oppositely from the location of a blade for inserting a print therebetween.
JP 2848982 describes a jaw cylinder equipped with an adjusting mechanism capable of adjusting a gap between a stationary member and a swing member in the jaw mechanism. This jaw cylinder has a jaw cylinder shaft rotatably supported on two opposite frames. A first member provided with the stationary member in the jaw mechanism and a second member provided with a swing member in the jaw mechanism are attached to the jaw cylinder shaft rotatably about the rotational centerline thereof. A transmission gear is interposed between the first and second members to rotate about the rotational centerline of the jaw cylinder shaft and mated with a gear located on the jaw cylinder shaft to rotate integrally with the jaw cylinder shaft. When the transmission gear rotates together with the jaw cylinder shaft, the first and second members rotate together. When the transmission gear turns relative to the jaw cylinder shaft using the torsion of the helical gear, the first and second members turn oppositely to move the swing member close to and apart from the stationary member. Alternatively, so as to rotate the first and second members in synchronization with the jaw cylinder shaft, the torsion of the helical gear in the gear mechanism for transmitting rotations from the jaw cylinder shaft to the first and second members can be employed. The first and second members turn about the rotational centerline of the jaw cylinder shaft oppositely to move the swing member close to and apart from the stationary member. This arrangement is operative to turn the first and second members relative to the jaw cylinder shaft. The gap between the stationary and swing members in the jaw mechanism can be adjusted by widening/narrowing the gap by an equivalent amount oppositely from the location of a blade for inserting a print therebetween.
The above-described conventional jaw cylinders have common subjects to be solved. In movable linkers and couplers, that is, in gear-mating sections, coupling sections between male and female screws, and movable fitting sections, among members employed to form the mechanism for adjusting the gap between the stationary and swing members, fine clearances provided for movement are integrated in an unstable condition. An adjusted amount of the clearance varies within a range summing these fine clearances, lacking accuracy and exhibiting extreme ambiguity. It is therefore difficult to correctly set the gap between the jaw portions of the stationary and swing members. Accordingly, if the jaw is too weak, a print is dropped off, causing paper jamming in the jaw folder and disturbing a paper rejection pitch that is originally constant. This is a disadvantage. In contrast, if the jaw is too strong, a print is broken, causing an obvious offset in images printed on adjacent pages. This is another disadvantage. In particular, a thin print to be gripped increases this trend.
The present invention has an object to provide a jaw cylinder in a jaw folder, which can correctly adjust a gap between a stationary member and a swing member in a jaw mechanism in accordance with a thickness of a print to be processed.
To achieve the above object, the present invention provides a jaw cylinder in a jaw folder, comprising: a first base including a stationary member in a jaw mechanism, said stationary member having a jaw portion; a second base including a swing member, said swing member having a jaw portion accessible to said jaw portion of said stationary member; and a third base having end axes at both ends, said third base rotatably supported by said end axes on a pair of opposite frames, said first base and said second base rotatably located on said third base about the rotational centerline of said third base, said first, second and third bases synchronously rotating to move said swing member close to and apart from said stationary member to grip a print therebetween, said jaw cylinder further comprising: a jaw clearance adjusting mechanism for turning said first and second bases about the rotational centerline of said third base in opposite directions to adjust a gap between said jaw portion of said stationary member and said jaw portion of said swing member in said jaw mechanism; a first force exerting mechanism for always exerting a force on said first base in the direction parallel with the tangent to a rotational trail of said first base; and a second force exerting mechanism for always exerting a force on said second base in the direction parallel with the tangent to a rotational trail of said second base.
In such the jaw cylinder according to the present invention, the jaw clearance adjusting mechanism is operative to turn the first base and the second base about the rotational centerline of the third base oppositely and equally. In this case, the stationary member arranged on the first base and the swing member arranged on the second base are displaced oppositely about the rotational centerline of the third base. As a result, the gap between the jaw portions of the stationary and swing members can be adjustably varied. At this moment, the first force exerting mechanism and the second force exerting mechanism always exert forces on the first base and the second base in the direction parallel with the tangent to the rotational trails. Therefore, a movable section in the jaw clearance adjusting mechanism is always pressed against one of corresponding sections by a fine clearance. Such the fine clearances, for movement in the circumferential direction about the rotational centerline of the third base or the direction of the gap between the jaw portions of the stationary member and swing member, are integrated always in one direction. Therefore, the fine clearances are not integrated in an unstable condition during the adjusting operation and an amount of adjustment does not lack accuracy.
In the jaw cylinder according to the present invention, preferably, the forces exerted from the first force exerting mechanism and the second force exerting mechanism direct oppositely. Preferably, the first force exerting mechanism and the second force exerting mechanism are arranged on the third base. Preferably, the first force exerting mechanism and the second force exerting mechanism are integrated and interposed between the first base and the second base.
In the jaw cylinder according to the present invention, preferably, the jaw clearance adjusting mechanism including: a first camshaft rotatably supported on said third base, and having a first eccentric cam located at a portion corresponding to said first base and a first gear located at a portion protruded from a side of said jaw cylinder to one of said frames; a second camshaft rotatably supported on said third base, and having a second eccentric cam located at a portion corresponding to said second base and a second gear located at a portion protruded from a side of said jaw cylinder to said one of said frames; a first slider fitted with said first eccentric cam and arranged on said first base only movable in the radial direction of said first base; a second slider fitted with said second eccentric cam and arranged on said second base only movable in the radial direction of said second base; a follower gear attached to a portion of said end axis of said third base protruded from said one of said frames and mated with a driver gear to transmit rotations to said third base; a gear mechanism rotatably supported on said one of said frames about the rotational centerline of said third base, and having a fourth gear located at a portion protruded to one side of said one of said frames and a third gear located at a portion protruded to the other side of said one of said frames, said third gear mating with said first gear and said second gear simultaneously; a transmission gear mechanism having a fifth gear mating with said follower gear and a sixth gear mating with said fourth gear, said fifth and sixth gears located integrally and rotatably about the same rotational centerline and movable in the direction parallel with the rotational centerline, at least one of said fifth and sixth gears and a gear mating therewith consisting of helical gears; and an adjusting mechanism for displacing said transmission gear mechanism in the direction parallel with said rotational centerline thereof.
In such the arrangement, the jaw clearance adjustment mechanism operates in the following manner. The adjustment mechanism is operative to move the transmission gear mechanism in parallel with the rotational centerline thereof. Among the helical gears in the transmission gear mechanism and the helical gears mating therewith, one at downstream of the drive transmission turns about its own rotational centerline due to the teeth torsion of another at upstream. Through the fifth gear and the sixth gear at downstream of the follower gear, the fourth gear at further downstream turns about its own rotational centerline (the same rotational centerline as those of three bases). When the fourth gear turns, the third gear integrally provided with the fourth gear turns, the first gear and the second gear mating with the third gear turn simultaneously, and the first camshaft and the second camshaft turn relative to the third base. When the first camshaft turns, the first eccentric cam located on this shaft turns within the first slider fitted with this cam to move the first slider in the radial direction of the first base. It also imparts a force to the first base through the first slider in one direction parallel with the tangent to the rotational trail thereof. In response to this force, the first base turns about its own rotational centerline (the same rotational centerline as that of the third base) in one direction. When the second camshaft turns, the second eccentric cam located on this shaft turns within the second slider fitted with this cam to move the second slider in the radial direction of the second base. It also exerts a force to the second base through the second slider in a direction parallel with the tangent to the rotational trail thereof and opposite to the direction of the force exerted to the first base. In response to this force, the second base turns about its own rotational centerline (the same rotational centerline as that of the third base) in a direction opposite to the direction of the first base. Accordingly, the stationary member located on the first base and the swing member located on the second base are forced to displace oppositely about the rotational centerline of the third base to adjust the gap between jaw portions of both members.
Also in this arrangement, the first force exerting mechanism and the second force exerting mechanism always exert opposite forces onto the first base and the second base. In this case, a movable section in the jaw clearance adjustment mechanism is always pushed against one of corresponding sections by a fine clearance. As a result, fine clearances for movement in the circumferential direction about the rotational centerline of the third base or in the direction of the gap between the jaw portions of the stationary member and the swing member are always integrated in one direction. Therefore, when the jaw gap is adjusted, the fine clearances are not integrated in an unstable state without lacking accuracy in an amount of adjustment.
Preferably, in the jaw cylinder according to the present invention, the jaw clearance adjusting mechanism includes a camshaft rotatably supported on said third base, and having a first eccentric cam located at a portion corresponding to said first base, a second eccentric cam located at a portion corresponding to said second base and a camshaft gear located at a portion protruded from a side of said jaw cylinder to one of said frames; a first slider fitted with said first eccentric cam and arranged on said first base only movable in the radial direction of said first base; a second slider fitted with said second eccentric cam and arranged on said second base only movable in the radial direction of said second base; a follower gear attached to a portion of said end axis of said third base protruded from said one of said frames and mated with a driver gear to transmit rotations to said third base; a gear mechanism rotatably supported on said one of said frames about the rotational centerline of said third base and having a fourth gear located at a portion protruded to one side of said one of said frames, and a third gear located at a portion protruded to the other side of said one of said frames, said third gear mating with said camshaft gear; a transmission gear mechanism having a fifth gear mating with said follower gear and a sixth gear mating with said fourth gear, said fifth and sixth gears located integrally and rotatably about the same rotational centerline and movable in the direction parallel with the rotational centerline, at least one of said fifth and sixth gears and a gear mating therewith consisting of helical gears; and an adjusting mechanism for displacing said transmission gear mechanism in the direction parallel with said rotational centerline thereof.
In this arrangement, the first eccentric cam and the second eccentric cam are located on a single camshaft. Except for this point, the jaw clearance adjusting mechanism has the same arrangement as the above arrangement. In a word, the single camshaft serves as replacement for the first camshaft and the second camshaft. Other operations are therefore similar to those of the jaw clearance adjusting mechanism in the above arrangement.
Preferably, in the jaw cylinder according to the present invention, the fifth gear and the sixth gear both consist of helical gears located at different torsion angles and/or torsion directions. In the jaw clearance adjusting mechanism thus configured, the magnitude of the displacement of the fourth gear caused from the operation of the adjusting mechanism matches a total of the displacement caused from the torsion of the fifth gear and the displacement caused from the torsion of the sixth gear. Except for this point, the jaw clearance adjusting mechanism has the same operation as that of the above-described jaw clearance adjusting mechanism.
Preferably, the jaw cylinder according to the present invention further comprises a repulsive mechanism interposed between the follower gear and the fourth gear, the repulsive mechanism always exerting a force on an eccentric location of the follower gear in one direction parallel with the tangent to the rotational trail of the follower gear, and always exerting a force on an eccentric location of the fourth gear in the direction opposite to the one direction parallel with the tangent to the rotational trail of the follower gear.
In the jaw clearance adjusting mechanism thus configured, the repulsive mechanism operates in between the follower gear and the fourth gear. To the fourth gear at downstream of the follower gear in the drive transmission, the repulsive mechanism always exerts a force in the tangent direction to the rotational trail thereof. The fourth gear turns about its own rotational centerline (similar to the rotational centerline of the follower gear) to always push one tooth surface against the corresponding tooth surface of the follower gear. In a word, free rotations caused from backlash between the follower gear and the fifth gear and backlash between the sixth gear and the fourth gear during rotations of these gears can be blocked. This is effective to prevent an unstable integration of the fine clearances corresponding to the backlash during the jaw clearance adjustment without lacking accuracy in an amount of adjustment.